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How can bone marrow transplantation treat some immune deficiencies?

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immune system disorder False-color scanning electron micrograph of a T cell infected with HIV (human immunodeficiency virus), the agent that causes AIDS (acquired immunodeficiency syndrome).

Bone marrow transplantation is a vital therapeutic approach for treating certain immune deficiency diseases, particularly those categorized as severe combined immunodeficiency (SCID).12

These disorders often result from a failure of precursor cells to differentiate into functional T or B cells, which are essential components of the immune system. By performing an allogeneic bone marrow transplant, healthy hematopoietic stem cells from a matched donor are introduced into the recipient. Once these donor cells engraft, they can produce new, healthy blood cells and functional immune system cells, effectively restoring the recipient's ability to mount an immune response.213

To ensure the success of the procedure, medical professionals carefully match the donor and recipient using human leukocyte antigen (HLA) markers to minimize the risk of graft-versus-host disease, a dangerous condition where the donor's immune cells attack the recipient's tissues. Additionally, patients typically undergo immunosuppressive drugs or radiation therapy to prepare their bodies to accept the new marrow.13